This is a very interesting topic, and I admit I do not understand the concept of oversharing quite well.
The point is this. I have a story, a very painful story with my ex, and what happened happened, and it is my history. I am mainly over it, but it is a part of my past. At first, I might have shared a lot, I might overshared, but honestly, I did not care. It was just getting out of me. And I felt relief. Then my ex validated everything I told people. And today, I can only shrug and say, it is what it is. There really is no need to even talk about it.
But, I had to evolve to that level, emotionally and mentally. It took some time. And the urge to share is not really there anymore. Maybe it was an initial phase followed by shock. And I thought I was losing my mind and I needed that feedback from people. I actually wanted to climb on top of a mountain and tell the story to the whole world.